When Eight is Not Enough

When eight is not enough.

By Bill Woods
Photos by TheBruntBros

Low 4s Zero-to-60 MPH times, and mid-11-quarter-mile blasts puts the Challenger at the head of its class. The SRT folks beat the snot of out the car with no problems—especially none from the stock Challenger rear. The Challenger SRT8 and Viper share the same Tremec 6-speed trans.

Dropping a Viper V10 into and LX (actually LC) platform Challenger, is so easy, it’s almost a no-brainer. And if Chrysler was in better financial shape, we’d bet you’d be seeing a Challenger SRT10 at your local Dodge dealer. Too bad. A Viper-powered Challenger would be a simple and sweet answer to the higher-powered/lower cost new Camaro, and blow the Shelby GT500 into the weeds for good measure. While the V10 Challenger, developed and built by Chrysler’s SRT group, has been seen before, taking it to production would have made sense in better times. But it’s always better times for the private Mo’shop or enthusiast with decent cobbling skills.

As with the 1968 Road Runner (which was built during better times), a Challenger SRT10 essentially is an exercise in dipping into existing parts bins. And like the beeper, the Challenger was built by SRT virtually in no time and for no money (OK, they did spend a couple of grand in miscellaneous hardware, if you want to get technical.). Here’s how it happened.

Tom McCarthy, SRT honcho, and a couple of his engineers, were sitting around one evening talking about cool cars and what they could do with the Challenger—especially with the expected big guns coming from Chevy and Ford. It seemed a natural to take a Viper engine and drop it into the Challenger. Tom gave the green light to the project, but with a few edicts: Spend no money. Make zero changes to the body. No cutting the engine compartment or the floorpan. The finished project had to be show quality as it would debut at ’08 SEMA, and it had to be presentable to management to demonstrate that they could build this package without touching the body.

Two engineers and two mechanics, working after hours on their own time (they weren’t paid a dime), were assigned to the project. SRT came up with a pre-production ’09 Challenger that was a post-durability car and was going to be scrapped. Cost: $0. The drivetrain came out of a Viper that had gone through a rear impact test. Cost: $0. The gang of four spent a month figuring it all out before turning wrench one. They did have the benefit of computer aided design (CAD), but the rest was trial and error. Start to finish took all of three months.

The biggest problem was the straight-shot Viper intake that made the V10 too long for the engine bay. The fix was a shaker hood. The two openings on the shaker hood are the actual intake, and the air is then routed through a circular path and into the stock Viper intake system—all courtesy of some free labor from the plastics shop at Chrysler Technical Center. Clearance issues also required moving the engine cooling module forward some 55mm. Also, a new driveshaft had to be fabbed due to the difference in length between the trans and rear in the Challenger and Viper. That, and some electronics work so the Viper engine could talk to the Challenger body, was essentially it.

SRT’s own performance testing of the Challenger SRT10 yielded unofficial numbers of zero to 60 MPH in the low 4s, and quarter-mile times in the mid 11s. The limiting factor here obviously was tires. The biggest street tire they could fit into the stock wheel well was a 285. Drag radials would have netted even better times.

When SRT presented the Challenger SRT10 to management they were totally blown away. But not blown away as much as Chevy and Ford losers would have been had they come up to this Challenger fender to fender.

The plastics shop at CTC came up with the neat-looking carbon fiber hood and decklid with spoiler. The front carbon spoiler is functional having been tested in “borrowed” time in the wind tunnel. It is not adjustable. The shaped mimics that on the Viper ACR..The turnbuckles keep it from flexing at speed. It provides significant downforce, and may even end up on a production vehicle.


The V10 is anchored in there with production Viper rubber mounts and cobbled brackets to fit the engine bay. Cooling module (fan and radiator) were moved two inches forward. Custom shaker directs air to stock Viper intake. The aluminum V10 weighs only 24 lbs more than the 6.1.Hemi, so weight distribution was not a problem. Jumpers were used between the Viper engine management systems for communication with the electrical architecture of the Challenger, not a big deal for the sparkies at SRT to handle. Resulting package is emissions compliant. Backyard swaps would rely on an aftermarket engine management system..


Largest-size tire the unmolested body could play host to was a 285. Wheels and brakes are stock and handle the extra power with no problem.


Since the distance between the trans and rear differs between the Viper and Challenger, the driveshaft was custom made.


The only interior mods were the Start button and gearshift knob borrowed from the Viper.



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